There is a continual focus on containment surrounding open-net pen fish farms. Farmers face challenges to their stock every day, whether it is predators looking for a free meal or adverse weather and changing environmental conditions. Ensuring enclosures are secure and stock is safe is enshrined in industry best practice. Regulations determine the design and strengths required for nets used. However vigilant farmers are, there is always a possibility of nets being damaged by predators or equipment. Ensuring a small problem doesn’t become a big issue requires nets to be regularly checked.
Inspecting nets is a mundane and boring task, but vital to ensure the integrity of all stock holding units. It is normally undertaken by divers on a routine basis or as part of the net washing process where operators assess net cleanliness with a camera. To undertake a thorough inspection takes significant dive time, especially with ever larger and deeper pens. Net cleaning teams are focused on net cleanliness rather than trying to catch sight of single broken net strands.
A Remotely Operated Vehicle (ROV) is good at repetitive tasks which require time underwater like inspecting nets and other equipment. It is limited only by the pilot’s need for a break and a reliable power source. Every dive is recordable and provides verified proof of net condition and where any broken strands may be located (identified at a depth and heading). With a move towards bigger pen sizes, the area of net to cover is continually increasing. Is it time to use ROVs in conjunction with divers to inspect and repair?
Changing the approach to Net repairs
Repairing a net is a skilled job requiring accuracy to undertake repairs and dexterity to ensure the repair provides net integrity and stock security. Underwater repairs to date have nearly always required the services of a diver. So why would you use an ROV system to inspect a net if you still need to get a diver to repair any issues? What if the ROV could undertake the net survey, affect a temporary repair and divers could then be used on a planned basis to permanently fix the net?
Development of a solution
Underwater Contracting (UCO) has been developing a secure and easily applied net repair patch over the last nine months. This will hook securely into the net without compromising it. It must be flexible to move with the net but strong enough to maintain integrity. It needs to be completely flat against the net, allowing net cleaners to continue to operate and deployable with an ROV system. NetFIX is a new and cost-effective way of making a temporary repair using an ROV to ensure net integrity, whilst allowing a planned time to undertake a permanent fix.
The Advantage of NetFIX
NetFIX is one of the tools developed by UCO to reduce cost, improve safety and reduce operational risk on fish farms by minimising the reliance on divers. UCO’s ROV deployed NetFIX requires a single operator and can be deployed easily from a workboat. It provides a secure, flat patch to maintain net integrity, allows net cleaners to continue to operate and gives time to plan a permanent repair.
Underwater Contracting (UCO) is a Scottish based company providing underwater services to the Aquaculture sector. The company specialises in the innovative design and engineering of diver-less underwater tooling for the aquaculture and energy industries. They use ROVs to provide a total mortality recovery service with the patented FOOVER® system and also undertake a range of surveys, including seabed surveys, anchor positioning, mooring condition and vessel surveys.
Featured: Example of net damage
1.: NetFIX system in operation